MORPHOLOGY OP BACTERIA 25 



certain disease-producing organisms, as the one causing 

 lumpy jaw in cattle. 



Classification of bacteria. Many attempts have been 

 made to erect a classification of bacteria comparable to the 

 classifications used in botany and zoology. The latter are 

 based on morphology. Due to the simple morphology of 

 the bacteria, a classification based thereon is unsatisfactory 

 and of limited value. For purposes of identification, not 

 only must morphology be considered, but also the action of 

 the organism on the food material, the physiology of the 

 organism, and the appearance of the masses of cells as they 

 occur in the artificial cultures of the bacteriologist, i. e. the 

 cultural characteristics. 



The classification that is in most common use is that of 

 Migula. It is as complete as possible where classification is 

 based on morphology alone. As modified by Buchanan 

 and presented in simple form, it is as follows : 



MIGULA'S CLASSIFICATION Ofr THE EUBACTERIA 



(Modified) 



(Forms of economic importance only) 

 Suborder I. Haplobacteria. Bacterial cells not permanently united 



into filaments, without sheaths. 

 Family I. Coccacece. Cells spherical, at least when free. 



1. Cells non-motile: 



a. Cell division in one plane, cells frequently remaining at- 

 tached in chains. . . Streptococcus 



6. Cell division in two planes (sometimes irregular), re- 

 sulting in formation of flat plates or of masses of 

 cells Micrococcus 



c. Cell division in three planes, all at right angles, the cells 

 remaining un%ed after division, forming cubes or 

 packets Sarcina 



2. Cells motile: 



a. Same as Micrococcus, but with flagella Planococcus 



6. Same as Sarcina, but with flagella Planosarcina 



Family II. Bacteriacece. Cells cylindrical in shape, not bent. 

 1. Cells, non-motile Bacterium 



